Activated magnetic biochar by one-step synthesis: Enhanced adsorption and coadsorption for 17β-estradiol and copper.

In this study, activated magnetic biochars (AMBCs) were successfully synthesized via one-step synthetic method with different temperature (300, 500 and 700 °C). Characterization experiments indicated that AMBCs had larger surface area, higher pore volume and more contained‑oxygen functional groups compared to the pristine biochar. In addition, AMBCs showed better adsorption performance for 17β-estradiol (E2) and copper (Cu(II)) in single/binary-solute systems than unmodified pristine biochar. AMBC-700 exhibited the highest capacity (153.2 mg/g) for E2, while the AMBC-300 showed the best adsorption capacity (85.93 mg/g) for Cu(II) in single-solute system. Adsorption of Cu(II) and E2 both followed by pseudo-second-order and Langmuir isothermal model. The initial pH of the solution had an effect on the adsorption of E2 and Cu(II) in single-solute system. Coadsorption experiments indicated that there existed site competition and enhancement of E2 and Cu(II) on the sorption in binary-solute system. Results from this study indicated that the E2 was adsorbed by hydrogen bonds, π-π EDA interactions. Cu(II) was mainly adsorbed via chemical complexation between contained‑oxygen functional groups and Cu(II) ions. Therefore, the AMBCs via one-step synthesis could be converted into value-added biochar as effective sorbent for simultaneous removal of E2 and Cu(II) from water.